Adsorption studies of Cu(II), Ni(II) and Zn(II) on Ajwain (Trachysperum copticum), a medicinal plant

Abstract

The removal of Cu(II), Ni(II) and Zn(II) ions onto Ajwain (Trachysperum copticum) was investigated using batch adsorption technique. The extent of adsorption was a function of pH, adsorbent dose, contact time and initial metal ion concentration. The adsorption of Cu(II), Ni(II) and Zn(II) was maximum at pH 5, 4 and 6 respectively. Experimental data were well fitted in Langmuir-type isotherm. The mean free energy in single and multi-metal-system indicated that adsorption of Cu(II), Ni(II) and Zn(II) was chemical in nature. Kinetic parameters for each kinetic model were calculated and discussed. The pseudo-second-order model was found to be best fit. Breakthrough capacity and desorption studies were carried by column process. The breakthrough capacities for Cu(II), Ni(II) and Zn(II) were found to be 39, 26 and 26 mg g−1 respectively in single metal system and reduced to 24, 21 and 18 mg g−1 respectively in multi-metal system.